1. Field of the Invention
The present invention relates to a pouch type lithium secondary battery, and more particularly, to a pouch type lithium secondary battery that is capable of improving saturation of an electrolyte by forming a containing space that contains an electrode assembly at one side of a multilayer-film pouch that forms a lower plate of a case, forming a gas chamber at the other side of a multilayer-film pouch that forms an upper plate of the case, and being formed for the gas chamber to connected with the containing space of the electrode assembly when a multilayer film pouch film is folded.
2. Description of the Related Art
A lithium ion battery is widely used for lightweight electronic appliances such as a mobile phone or a camcorder. Further, it is nature-friendly because it does not use heavy metals such as mercury (Hg) or cadmium (Cd). The lithium ion battery has a large output and capacity compared with conventional batteries.
The lithium ion secondary battery is divided into a lithium metal secondary battery that uses a lithium metal as a negative active material and a lithium ion secondary battery that uses carbon substance as a negative active material. Since the lithium ion secondary battery doesn't use a lithium metal that has a high reactivity, it is more stable as compared to a lithium metal secondary battery. The lithium secondary battery is divided into prismatic-type, cylindrical-type, and pouch type. The prismatic-type lithium ion secondary battery whose bare cell is fabricated by inserting an electrode assembly which is wound in a jelly-roll type to a rectangular-pole-shaped can, sealing the can with a cap assembly and injecting an electrolyte through an electrolyte inlet in the can. The cylinder type lithium secondary battery whose bare cell is fabricated by inserting an electrode assembly which is wound in a jelly-roll type to a cylinder type can, sealing the can with a cap assembly and injecting an electrolyte through an electrolyte inlet in the can. The pouch type lithium secondary battery whose bare cell is fabricated by inserting an electrode assembly which is wound in a jelly-roll type to the multilayer-film pouch formed by coating polymer at the inside of metal foil, sealing the multilayer-film pouch and injecting an electrolyte through a gas chamber.
Further, the lithium secondary battery is divided into a lithium secondary battery that uses a liquid electrolyte depending on the type of the electrolyte, and a lithium polymer battery that uses the solid polymer as an electrolyte. The lithium polymer battery classifies into a solid type that does not include an organic electrolyte, and a gel type that includes an organic electrolyte.